Certain dates in history are stuck in my memory - 1492, 1776, 1941, 1945 - good to know but not necessary for daily conversational use. However, it really is more than a mere a courtesy to remember significant family dates, especially your wedding anniversary and the dates of your children's birthdays. Everyone else's statistics can be easily accessed if necessary, but to forget those familial dates is asking for trouble.
Other numbers have a degree of importance and probably should be memorized, such as one's social security number. Seriously, it is very embarrassing when asked for it in an important exchange and not be able to give it without checking your identification card, which may or may not be buried in your purse. That is almost as ridiculous as not knowing your cell phone number - just saying...
Although I once thought of myself as being a number-oriented person, I now realize that skill is completely different and useful, and has little or nothing to do with retaining number-related drivel only I might understand, and there is a lot of it. I mean, think about it, how often does the need to know the number of cards in a pinochle deck come up in conversation?
As if I do not already have enough useless figures in my head, the basic weights and measures conversions I have cemented in there have been tampered with. To me, there will always be four quarts in a gallon, except now, when I purchase a "half-gallon" of ice cream I get only about a quart and a half, as measured in "that other system," which I never mastered beyond "liter is capacity, gram is weight, and meter is distance" - why measure a 39.37-inch meter when a 36-inch yard is so much easier? Never mind, I probably would not understand anyway.
Then there are the constantly fluctuating numbers at the gas pumps. There was a time not that long ago when gasoline remained the same price long enough to factor that amount into the budget. Today, trying to remember the cost of gasoline is ridiculous, although I foolishly mentally note the amount as it changes from one day (hour?) to the next --- as for that nine-tenths business, I am convinced it is just an annoying way to get another penny per gallon from drivers.
Another example. As I sit here writing, I can tell you I once went without coffee for five years and nine months, which has no meaning to a non-coffee drinker, or anyone else, actually.
Those are but some of the countless insignificant bits of useless trivia that have taken up residency in my brain along with: the weight of a shark's liver (do not even ask); knowing all digital numerals are formed by rearranging seven small lines; the number of steps from floor to floor in our house (and the house before this one as well); and having my tonsils removed when I was 7 years old at 7 a.m. on July 7, 1947. Really thrilling stuff.
My mind overflows with assorted numbers which, for the most part, have little or no real function and serve no constructive purpose. Unfortunately, they also leave little or no room for remembering more important numbers: my cell phone number, license plate, checkbook balance.....
Did I mention I once went five years and nine months without coffee? It seemed like it lasted so much longer than that -- more like the number of years since the Browns have won a championship --- but who's counting?